Packaging machine



R. G. NUTTING ETAL Re. 26,553

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PACKAGING MACHINE Original Filed April 10, 1961 Sheet of 16 lvfigww-o 12066411 2: l ichard C. w denneih OJ. 8); n' rZ'Emre/o 4 M? AM 11.4% 4am United States Patent 26,553 PACKAGING MACHINE Robert G. Nutting, Glenview, Richard C. Wagner, Clarendon Hills, and Kenneth K. Christensen, Winfield, Ill., assignors, by mesne assignments, to Bartelt Engineering Company, Inc., Rockford, Ill., a corporation of Delaware Original No. 3,230,687, dated Jan. 25, 1966, Ser. No. 102,048, Apr. 10, 1961. Application for reissue July 11, 1966, Ser. No. 570,112

Int. Cl. B6511 9/08, 3/30, 47/06 U.S. Cl. 53-180 Claims Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

This invention relates to a machine for forming, filling and closing flexible walled bags and, more particularly, to a machine in which the bags are formed by heat sealing two strips of packaging material transversely to form a series of connected bags and in which the bags are severed and advanced by a carrier through closing and filling stations.

One object of the invention is to provide in a machine of the above character a novel sealing mechanism which permits the bags to be made While the strips move with a continuous motion and at a high rate of speed and which, nevertheless, forms the seals accurately and neatly.

A more detailed object is to impart an orbital motion to the sealing mechanism so that the latter moves with the strips to form the seals and then away from the strips.

The invention also resides in the provision of a novel mechanism for cutting the seals intermediate their edges to sever the end bags on the strips.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which FIGURE 1 is a perspective view of a packaging machine embodying the novel features of the present invention.

FIG. 2 is an enlarged perspective view of a package made on the machine.

FIG. 3 is a schematic perspective view illustrating the steps performed on the machine.

FIG. 3a is a schematic perspective view forming a continuation of the right-hand side of FIG. 3.

FIG. 4 is a schematic view illustrating the drive to the various mechanisms.

FIG. 4a is a schematic view forming a continuation of the right-hand side of FIG. 4.

FIG. 5 is an enlarged sectional view taken along the line 5-5 in FIG. 1, parts being broken away and shown in section.

FIG. 6 is an enlarged perspective view of the heat sealing bars.

FIG. 7 is a sectional view taken along the line 7-7 in FIG. 5, parts being broken away and shown in section.

FIG. 8 is a sectional view taken along the line 8-8 in FIG. 5.

FIG. 9 is an enlarged fragmentary sectional view taken along the line 9-9 in FIG. 13.

FIG. 10 is an enlarged fragmentary plan view of the mechanism for cutting the bags from the strips.

Reissuecl Mar. 25, 1969 FIG. 11 is a fragmentary perspective view of the mechanism used for guiding the bags.

FIG. 12 is a fragmentary plan view of the parts shown in FIG. 11 but with the parts in a different position.

FIG. 13 is a diagrammatic plan view of the mechanisms for severing the bags and transferring the bags to the carrier.

FIG. 14 is an enlarged fragmentary perspective view of one of the clamps used to hold a bag on the carrier.

FIG. 15 is a perspective view of the mechanism for delivering the severed bags to the carrier.

FIG. 16 is a fragmentary front elevational view of the forward end of the carrier, parts being broken away and shown in section.

FIG. 17 is a fragmentary sectional view taken along the line 17-17 in FIG. 16.

FIG. 18 is a fragmentary sectional view taken along the line 18-18 in FIG. 16.

FIG. 19 is a fragmentary front elevational view of the filling mechanism, parts being broken away and shown in section.

FIG. 20 is an enlarged fragmentary sectional view taken along the line 20-20 in FIG. 1.

FIG. 21 is an enlarged fragmentary plan view of the filling mechanism, parts being broken away and shown in section.

FIG. 22 is an enlarged fragmentary sectional view taken along the line 22-22 in FIG. 1.

FIG. 23 is a fragmentary sectional view taken along the line 23-23 in FIG. 22.

FIG. 24 is a fragmentary plan view of the mechanism for unloading the bags from the machine.

As shown in the drawings for purposes of illustration, the invention is embodied in a machine for forming, filling and closing a pouch or bag which is composed of two rectangular panels 31 disposed face to face and joined together at their margins preferably by a fold at the bottom and heat seals 32 and 33 at the top and sides respectively. Herein, the bags are made from a web 34 of sheet material either composed of or coated on one side with a thermoplastic material and drawn off a supply roll 35. The web is folded longitudinally (see FIGS. 3 and 3a) and the two resulting strips 34 are heat sealed together transversely at spaced intervals as indicated at 36 to form a series of connected bags. The latter then are separated by cutting the seals 36 intermediate their edges so that each seal forms the trailing side seal 33 of one bag and the leading side seal of the next bag. After being separated from the web 34, each bag is filled with the product to be packaged and then is closed by the top seal 32.

The various mechanisms for advancing, folding and cutting the web 34 and for advancing, filling and closing the bags 30 are mounted on an elongated, horizontal base 37 and are operated in timed relation to each other by a horizontal shaft 38 (FIGS. 4 and 4a) journaled in and extending lengthwise of the base. The supply roll is supported on the end of the machine base 37 by a bracket 39 and the web 34 is drawn off the roll and over a plow 40 which is located at a station 41 and which folds the web longitudinally, the web being advanced in this case by two sets of feed rollers 42 and 43 spaced along the base (FIGS. 1 and 4). From the folding station, the web is advanced to a station 44 where the cross seals 36 are formed and then to a cut-off station 45 where the successive end bags are severed from the web. After being cut from the web, the bags are carried edgewise by a conveyor 46 which carries the bags first through a filling station 47 and then through a top sealing station 48. As shown in FIG. 16, the conveyor may take the form of an endless chain 194 one run of which forms an extension of the path of the web 34 and the bags are supported in spaced relation on this run by grippers or clamps 50.

According to the present invention, the various mechanisms for forming, filling and closing the bags 30 are constructed and correlated with each other in a novel manner so that the web 34 and the bags on the conveyor 46 may move continuously and at a comparatively high speed to produce a large number of completed packages per minute while maintaining the accuracy of the fill and the overall neatness of the packages. To these ends, the mechanisms are constructed so that they may perform their individual functions in periods larger than in prior machines of this type and yet still produce packages at a higher rate.

In general, the high rate of production is achieved while the accuracy and neatness of the package is maintained by arranging the operating mechanisms to move with the web 34 and the bags 30 as they are performing their packaging functions but to operate with the same precision and ruggedness as the corresponding mechanisms of appreciably slower machines heretofore employed. Thus, the mechanism 51 for forming the cross seals 36 firmly engages the web without stretching or wrinkling the latter to make strong, neat and accurately spaced seals. Similarly, the bags are positively held open preparatory to filling, the air in the bag is displaced first by the filling mechanism 52 rather than by the product and the bags are filled from the bottom, all this being accomplished over a comparatively long period in spite of the high speed production of the machine. Also, the top seals 32, like the side seals 33, are made precisely to maintain the attractive appearance of the bag.

In the present instance, the shaft 38 (FIG. 4) for driving the operating mechanisms is journaled in bearings 53 and is rotated continuously by a motor 54 through speed reducing chain drive 55. Both sets of feed rolls 42 and 43 are driven in unison from a common shaft 56 which is journaled on the base 37 parallel to the drive shaft 38 and driven, in turn, by the latter through a chain 57, an intermediate shaft 58 and a chain 59. The feed rolls 42 are rotatably supported on opposite sides of the web 34 by a bracket 60 (FIG. 1) which is mounted on the base 37 in advance of the sealing station 44. Meshing gears 61 (FIG. 4) fast on the rolls drive the latter together but in opposite directions and are driven from the shaft 56 through bevel gears 62. Similarly, the feed rolls 43, which are journaled in a bracket 63 on the opposite side of the sealing station, are driven from the shaft 56 through bevel gears 64 and meshing gears 64 on the lower ends of the rolls. One roll of the set 43 has a rubber covering 66 which stops short of the fold line of the web and prevents excessive creasing. The rolls 42 and 43 draw the web 34 from the supply roll 35 and across the plow 40 which may be of well-known construction and comprises a stationary triangular plate 67 supported on the base 37 and inclined downwardly, the web being folded around the plate by upright idler rollers 68.

In order that the operating parts of the sealing mechanism 51 may move with the web 34 to provide a sufficient period for heat sealing the web and still form neat seals 36 without stretching or wrinkling, this mechanism includes two units 69 and 70 each of which carries a plurality of sealing bars 71 (see FIGS. and 8) opposing the bars on the other unit and the two units are given an orbital movement. Thus, the units move together and into engagement with opposite sides of the web and then move along with the web at the same speed at which the latter is advancing. During the period in which the sealing units 69 and 70 are traveling with the web, the bars 71 form a plurality of cross seals 36 and then the units are backed away from the web. The orbital path is completed by the units moving back in a direction opposite to the web advance. In this way, the bars 71 may be supported firmly on the units against twisting and yet may be individually yieldable to produce the optimum pressure for making the seals 36.

To give each of the sealing units 69 and 70 the desired orbital motion, each unit is supported and moved by carriers herein in the form of endless chains disposed above and below the unit. Thus, as shown in FIGS. 5, 7 and 8, the front sealing unit 69 is connected to a pair of endless chains 72 above the unit and a similar pair of chains 72' below (see FIG. 3). In the same manner an upper pair of chains 73 and a lower pair 73 (FIG. 7) support the rear sealing unit 70, the construction for the two units being substantially the same. Thus, the upper chains 73 are disposed end to end and adjacent ends are driven by sprocket 74 (FIG. 4) whose shafts 75 are journaled in a horizontal stationary plate 76 (FIG. 5). The latter is supported on a similar plate 77 which is disposed beneath the sealing units 69 and 70, through the medium of upright posts 78 spanning extensions on the rear of the plates. The posts are bolted to both plates and the lower plate 77 is secured rigidly to the base 37 so that the two plates and the posts form a C-shaped bracket for supporting the sealing units.

The outer ends of the upper chains 73 are guided around rollers 79 which are journaled between the legs of U-shaped supports 80 (FIGS. 7 and 8) which slide laterally in slots 81 cut in the ends of blocks 82 depending from the upper plate 76. The supports 80 are urged outwardly by compression springs 83 to maintain the chains 73 under the desired tension. The similar pair of chains 72 supporting the upper end of the front sealing unit 69 are driven by sprocket wheels 86 fast on shafts 87 (FIG. 4).

Also, these chains extend around rollers journaled in supports which slide in blocks and are urged outwardly by compression springs, these parts being the same as used in connection with the chains 73. The lower chains 73 for the sealing unit 70 and the chains 72' for the unit 69 are substantial duplicates of the upper chains and the corresponding parts are indicated by the same but primed reference characters.

All of the chains for both sealing units 69 and 70 are driven in unison from the drive shaft 58 through bevel gears 88 (FIG. 4) and an upright shaft 89 which spans the plates 76 and 77 and is journaled in bearings 90 (FIG. 5) in gear housings 91 bolted to the plates. A gear 93 (FIGS. 4, 5 and 8) keyed to the upper end of the shaft 89 drives a gear 94 meshing with one of the gears 95 on the rear sprocket wheel shafts 75. The gear 96 meshing with both of the gears 95 completes the drive to these two shafts and also drives the front chains 72 through an idler gear 97 and gears 98 on the front sprocket wheel shafts 86. A similar gear train drives the lower chains as indicated by the primed reference characters in FIG. 4.

Each of the sealing units 69 and 70 includes a rigid supporting portion 99 which is mounted on the associated chains at Widely spaced points to provide a stable mounting for the sealing bars 71 while permitting the latter to be individually yieldable. As shown in FIGS. 5 and 7, this support 99 for the unit 70 is formed by two elongated bars 100 which extend horizontally one above the other lengthwise of the sealing unit, that is, parallel to the path of the web 34. The two bars are held apart by spacers 101 which are clamped rigidly between the bars by bolts 102. The support 99 is connected to alined links of one of the sets of chains 73 and 73' by a vertical pin 103 (FIG. 7) which is pinned to these links and journaled in hearings 104 in the bars 100. An enlarged central section 105 of the pin provides shoulders 106 which abut the bearings 104 and prevent the support 99 from moving relative to the pin. A similar pin mounts the support on the other set of chains 73 and 73 and, in the same manner, the support 99 of the front unit 69 is mounted on the chains 72 and 72'. With the foregoing arrangement, the sealing bar supports 99 remain precisely parallel to the path of the web 34 while they follow their orbital paths.

The sealing bars 71 on the front unit 69 are received and secured in vertical slots 107 cut in spaced blocks 108 (FIGS. 5 and 6) which are carried on the ends of horizontal screws 109. The latter slide in holes 110 in the inner sides of the bars 100. The holes open into enlarged bores 111 which house compression springs 112 acting between heads on the screws 109 and plugs 113. The latter are threaded into the outer ends of the bores to adjust the compression of the springs and hence the force with which the sealing bars 71 are urged outwardly.

While the sealing bars 71 on the rear unit 70 may also be supported yieldably as are the bars on the front unit 69, it is preferred to mount these rigidly. For this purpose, the bars are received in blocks 108 similar to the blocks 108 and these blocks are carried by screws 109 which, like the screws 109, project into holes 110 in the bars 100 of the unit 70. In this case, however, spacers 114 surround the screws between the blocks 108' and the bars 100 and the screws are tightened to clamp the blocks rigidly against the spacers.

In the present instance, the support 99 of each sealing unit 69 and 70 carries eight sealing bars 71 and the bars on one unit directly oppose the bars on the other. Thus, eight cross seals 36 are made each time the two sealing units come together. Preferably, the bars do not act directly on the web 34, but instead, act through a sheet 115 (FIGS. 7 and 8) of a material which is heat resistant but which transmits heat and does not stick to the web. A suitable material for this purpose is sold under the trade name Teflon by E. I. du Pont de Nemours. One such sheet is used with each sealing unit and extends throughout the length of the unit across the sealing faces of the bars 71. The ends of the sheet 115 are bent back around curved guides 116 carried by the support 99 and clamped between jaws 117 on the bars 100. Embedded in each sealing bar 71 is an electric heating coil 118 (FIG. 6) which maintains the bar at the proper temperature for forming the heat seals 36.

In addition to the advantages of the sealing mechanism 51 as enumerated previously, this mechanism also permits the heating coils 118 to be connected to power lines easily and without the use of commutator rings. Thus, power from a suitable source is connected through rheostats 119 (FIG. 1) in a control panel 120 and then to a signal box 121 mounted on the plate 76. From the box, flexible leads 122 extend to the ends of each sealing unit 69 and 70 and then through a conduit 123 on the associated support 99. Each conduit is formed from a channel 124 (FIG. 5) extending along the outside of the support between the bars 100 and a cover 125. The channel is held is place by screws 126 threaded into the spacers 101 and by washers 127 abutting the bars 100 and projecting into slots in the channel. The individual heating coils 118 are connected to the leads 122 by wires 128 extending through the support 99 to the conduit 123.

To provide a backing for the sealing uints 69 and 70 as the latter are pressed against the webs 34 and thereby increase the rigidity of the mounting of the sealing bars 71, rollers 129 and 129' (FIGS. 5 and 7) are journaled on the upper and lower end portions of the pins 103 and ride along stationary guides 130 and 130' which are supported on the plates 76 and 77 through the medium of the blocks 82. The rollers 129 and 129' are held in position by sleeves 131 which encircle the pins 103 and abut against the bearings 104 so that the chains 73 and 73' (or 85 and 85), the rollers 129 and 129' and the support 99 are vertically rigid relative to each other. To prevent the chains from sagging, flanges 132 project laterally from the lower ends of the upper guides and the ends of the upper rollers 129 ride on these flanges.

In order that the sealing bars 71 on one of the units 69 and 70 may initially be alined with the bars on the other unit, the shafts 75 and 87 are connected to their respective sprocket wheels 74 and 86 through identical manual clutches 133 (FIG. 7). The clutch for the sprocket wheel 74, for example, includes a cylinder 134 received in a mating counterbore 135 in the sprocket wheel 74 and drawn up into the counterbore by a bolt 136 projecting through the shaft 75. On the upper side of the cylinder is a squared lug 137 which is received in a complementary notch in the end of the shaft which has a running fit with the sprocket wheel. When the cylinder is drawn tight in the counterbore, the cylinder is connected to the shaft through the lug and frictionally drives the sprocket Wheel. By loosening the bolt 136, the sprocket wheel is disconnected from the drive and the chain 73 may be moved by hand to its proper position relative to the other parts.

With the sealing mechanism 51 constructed as described above, the machine may easily be arranged so that it alway stops with the sealing bars 71 withdrawn from the web. Thus, there is no danger that the web will be overheated from prolonged contact by the sealing units 69 and 70 when the machine is standing idle. For this purpose, the motor 54 is controlled through well-known circuitry by a switch 138 (FIG. 4) actuated by a cam 139 on the drive shaft 38. The cam is shaped to actuate the switch only in that portion of the machine cycle in which the sealing units are Withdrawn and the control of the motor 54 is arranged so that it cannot be stopped until the switch is actuated.

When the cross seals 36 have been made to form a series of connected bags, the latter are advanced by the feed rolls 43 to the cut-off station 45 where the terminal bag is severed from the strip. The cutting is effected by knife units 140 and 141 disposed on opposite sides of the web and operable to cut the web transversely intermediate the edges of each seal 36. As shown in FIGS. 3 and 4, the knife units 140 and 141 comprise upright drums 142 and 143 journaled on the base 37 by means of shafts 144 and 145 (FIG. 4) to turn about their longitudinal axes. The drums are turned continuously from the drive shaft 58 and carry cutter elements 146 and 147 (FIGS. 10 and 13) respectively which cooperate with each other to sever the end bag.

Herein, the cutter elements 146 are in the form of elongated bars made of hardened steel and having square cross sections to be received in V-shaped grooves 148 cut lengthwise in the periphery of the drum 142. Preferably, there are four such bars and, when they are positioned in the grooves 148, one corner 149 projects radially outwardly of the drum and serves as a knife edge. To hold the bars in place in the grooves. two flat surfaces 150 are formed on opposite sides of the drum 142, these surfaces extending from one groove to the next groove and being generally alined with the exposed sides of the bars 146, and plates 151 are clamped to the flat surfaces 150 by means of bolts 152 to abut against the bar sides. In this way the bars are held securely on the drum 142 but may easily be removed and turned to expose a different corner when the corner being used becomes dull.

In the case of the knife unit 141, the cutter elements 147 also are bars identical to the bars 146 but are held with a flat side 1S3 tangentially disposed relative to the drum 143. Thus, the sides 153 serve as anvils for the knife edges 149 so that a knife edge and an anvil cooperate to make each out (see FIG. 10). Each bar 147 is held between two parallel, yieldable jaws 154 which project outwardly from the drum 143 and are drawn together by bolts 155 which project through one jaw and are threaded into the other. By making the bars 147 the same as the bars 146, the two sets may be interchanged after all four corners of each of the bars 146 have dulled so that the bars 147 then provide the knife edges while the bars 146 serve as the anvils. In this Way, the eight bars originally installed on the machine provide thirtytwo knife edges or eight complete changes without replacement.

To drive the drums 142 and 143, a vertical shaft 156 (FIG. 4) is journaled on the base 37 and is driven from the drive shaft 58 through bevel gearing 157. A gear 159 keyed to the upper end of the shaft 156 meshes with an idler gear 160 which, in turn, meshes with a gear 161 on the lower end of shaft 144 of the drum 142. A second gear 162 keyed to this shaft meshes with a gear 163 equal in size and keyed to the shaft 145 of the drum 143 so that the two drums are turned in unison but in opposite directions.

Although the bags 30 are edge-to-edge when attached to the web 34, they are spaced apart when carried by the conveyor 46 so as to permit more accurate and neater filling and closing operations. To effect such spacing, the conveyor is driven at a faster speed than the web. For example, the linear speed of the web may be about 16 inches per second while the conveyor may move at a speed of approximately 22 inches per second. In order that each bag 30 as it is cut from the web is delivered to a clamp 50 (FIG. 14) on the conveyor, it is accelerated and momentarily moves at a speed faster than the conveyor.

To transfer the severed bag 30 from the web 34 to the conveyor 46 and, at the same time, to speed up the rate of travel of the bag, an accelerating mechanism 164 is disposed between the cut-off station 45 and the adjacent end of the conveyor. The accelerator 164 includes a first pair of vertical rollers 165 and 166 (FIG. 13) which receive the leading edge of the end bag on the web just before this bag is cut by the knife units 140 and 141. The timing is such that the rollers 165 and 166, which are turning at a higher peripheral speed than the Web advance, slip momentarily as the bag is out. These rollers then accelerate the bag and deliver it between a second pair of rollers 167 and 168 which are turning at the same speed as the first pair and the second pair of rollers, in turn, delivers the leading edge of the bag to one of the clamps 50 on the conveyor 46. Since the peripheral speed of the rollers 167 and 168 is greater than the linear speed of the conveyor and since the clamp is closed before the bag is released by these rollers, the bag will buckle slightly during the transfer. Such buckling insures that the bag is inserted completely in the clamp and properly positioned for subsequent operations. Preferably, a second complete set of rollers 165, 166', 167 and 168' are disposed below the rollers 165, 166, 167 and 168 so that the bag is engaged at vertically spaced points and kept upright (FIG.

The rollers 165 and 165' are fast on a shaft 169 which is journaled on the base 37 while the rollers 167 and 167 turn with stub shafts 170 projecting toward each other from the top and bottom of the bracket 63 (FIG. 1). This leaves a pocket 171 through which each clamp 50 may pass as it enters the position in which it receives a bag. The rollers 165, 165', 167 and 167' are driven from the shaft 38 through the medium of the conveyor 46 whose shaft 172 (FIG. 4) carries a gear 173 meshing with a gear 174 on the lower stub shaft 170. Through an idler gear 175, the gear 174 drives a gear 176 keyed to the lower end of the shaft 169. A gear 177 keyed to the upper end of that shaft meshes with an idler gear 178 which, in turn, meshes with a gear 179 on the upper stub shaft 170.

The rollers 166 and 166 are urged into frictional engagement with the rollers 165 and 165 to be driven thereby and, for this purpose, the rollers 166 and 166' are journaled on opposite ends of an upright shaft 180 which is supported on the free ends of horizontal levers 181. The latter is fulcrumed on a vertical post 182 upstanding from the base 37. The post also serves as a fulcrum for a second pair of levers 183 whose free ends are clamped by bolts 184 to a shaft 185. Also clamped to the shaft by bolts 186 are arms 187 whose free ends support a shaft 188 on which the rollers 168 and 168' are journaled. Thus, the latter may be urged into driving engagement with the rollers 167 and 167' and by adjusting the levers 183 and the arms 187 on the shaft 185, the rollers 168 and 168' can be moved forward or back relative to the rollers 167 and 167 to direct the bag 30 properly into the clamp 50.

To urge the rollers 166 and 166 toward the rollers and 165' and the rollers 168 and 168' toward the rollers 167 and 167, a horizontal bar 189 spans the shafts and 188 and enlarged ends on the bar abut against these shafts. A pin 190 projects through the center of the bar and is threaded into the post 182 and a compression spring 191 encircling the pin acts between the bar and a washer 192 on the pin. The washer is adjustably held in place by nuts 193 threaded on the end of the pin.

Herein, the conveyor 46 comprises an endless chain 194 (FIGS. 16 and 17) disposed in a horizontal plane with a straight run 195 extending from a point adjacent the accelerator 164 through the filling and closing stations 47 and 48, the return run being behind the run 195. At its forward end, the chain extends around a sprocket wheel 196 (FIG. 4) which is keyed to the shaft 172, the latter being the shaft which drives the accelerator. The other end of the chain extends around a sprocket wheel 197 (FIG. 4a) keyed to the upper end of a vertical shaft 198 which is journaled on the base 37 and driven by the shaft 38 through bevel gears 199. For the sake of rigidity, a second chain 194' also is employed and is disposed below the chain 194 to extend around the roll 196 and a sprocket wheel 197' on the shafts 172 and 198. Spanning the chains at horizontally spaced points are vertical blocks 200 (FIG. 16) which are fastened to the chains by pins 201.

To increase the rigidity further, the two chains 194 and 194 are guided positively along both the active run 195 and the return run. Thus, the rollers 202 (FIG. 18) of the upper chain 194 ride in a track 203 on the active run and in a track 204 on the return run while the lower chain 194 rides in similar tracks 203' and 204'. The lower tracks are defined by elongated bars 205 secured to the base 37 and extending horizontally between the roll 196' and the sprocket wheels 197. Inturned flanges 206' on these bars engage the rollers 202 of the chain 194' on the outside. On the inside, these rollers ride on the edges of a horizontal plate 207' which spans the roll and the sprocket wheel and is fixed to tubular posts 206 upstanding from the base 37.

As each roller 200' of the chain 194' leaves the roll 196' and enters the run 195, it crosses a gap before the end of plate 207 and bar 205'. This is the point at which each clamp 50 on the conveyor 49 is receiving a bag 30 from the accelerator 164 and, accordingly, means is provided to maintain the rigidity of the chain through this gap. This means comprises an extension 209 of the plate 207' reduced in thickness and received in a slot 210' (FIG. 18) cut in the outer side periphery of the roll 196'. The extension 209' projects forwardly from the end of the plate 207' tangentially of the roll 196'. The upper tracks 203 and 204 are similarly formed by an inside plate 207 and two outside bars 205. In this case, however, the bars are fastened to a bracket 211 which is secured to the post 208.

As shown in FIG. 16, the clamps 50 are mounted on supports 212 which, in turn, are bolted to the blocks 200. Each clamp opens rearwardly and comprises a stationary inner jaw 213 (FIG. 15) and a movable outer jaw 214. The inner jaw is formed by a block and a U-shaped strip 215 of spring steel extends around the leading edge of the block. The inner leg 216 of the spring 215 is fastened to the back of the block 213 while the outer leg constitutes the movable jaw 214. The end 217 of the 

